Relationship of photographic indices and NDVI values to dry biomass production in triticale in the Mexicali valley

Abstract

Objective: To determine the relationship of different photographic indexes and NDVI
values with the production of dry biomass of leaves in triticale forages (x Triticosecale
wittmack).
Design/methodology/approach: Ten triticale varieties were grown during two
agricultural cycles, under different irrigation and fertilization conditions. Data was
analyzed under a randomized complete block design. Three samples were taken to
estimate the production of dry foliar biomass, before, and after anthesis. In each
sampling, three photographs were taken with a digital camera and NDVI measurements
were made with the greenseeker® spectroradiometer; subsequently, destructive
sampling was carried out to estimate dry leaf biomass.
Results: The results showed a better fit to the simple linear regression equations
between NDVI and leaf biomass before anthesis (R 2 =0.45) in response to the effects of

interaction between samples and varieties in both evaluation cycles. After anthesis, the
statistical relationship between NDVI and leaf biomass was lower (R 2 =0.34). In addition,
the ratio between the GGA index and leaf biomass before anthesis was (R 2 =0.30),
similarly a higher relationship (R 2 =0.34) was found between GGA with leaf biomass after
anthesis.
Findings/conclusions: It is possible to effectively use either GGA or NDVI indexes as
an indirect method to estimate dry biomass through the use of digital cameras or
greenseeker®., due to the positive linear relationship (R 2 = 0.85) between the two
indexes.